We had an expansive run in the ’60s and ’70s. You might have thought, as I did then, that our species would be on Mars before the century was over. But instead, we’ve pulled inward. Robots aside, we’ve backed off from the planets and the stars. I keep asking myself: Is it a failure of nerve or a sign of maturity?

Maybe it’s the most we could reasonably have expected. In a way, it’s amazing that it was possible at all: We sent a dozen humans on week-long excursions to the Moon, missions that returned a wealth of data, but nothing of short-term, everyday, bread-on-the-table practical value, or at least not much.

They lifted the human spirit, though.

They enlightened us about our place in the Universe. A highly visible program affecting our view of ourselves might clarify the fragility of our planetary environment and the common peril and responsibility of all the nations and peoples of Earth.

There’s something more. Spaceflight speaks to something deep inside us many of us, if not all. A scientific colleague tells me about a recent trip to the [part pf the Planet we call the] New Guinea highlands where she visited a stone age culture hardly contacted by Western civilization. They were ignorant of wristwatches, soft drinks, and frozen food. But they knew about Apollo 11. They knew that humans had walked on the Moon. They knew the names of Armstrong and Aldrin and Collins. They wanted to know who was visiting the Moon these days.

Projects that are future-oriented, that, despite their political difficulties, can be completed only in some distant decade are continuing reminders that there will be a future. Winning a foothold on other worlds whispers in our ears that we’re more than Picts or Serbs or Tongans.

We’re humans.

In meantime people everywhere hunger to understand. The idea that we’ve now understood something never grasped by anybody who ever lived before. That exhilaration, especially intense for the scientists involved, but perceptible to nearly everybody propagates through the society, bounces off walls, and comes back at us. It encourages us to address problems in other fields that have also never before been solved. It increases the general sense of optimism in the society. It gives currency to critical thinking of the sort urgently needed if we are to solve hitherto intractable social issues. It helps stimulate a new generation of scientists.

The more science in the media, especially if methods are described, as well as conclusions and implications the healthier, I believe, the society is. There’s plenty of housework to be done here on Earth, and our commitment to it must be steadfast. But we’re the kind of species that needs a frontier for fundamental biological reasons.

Every time humanity stretches itself it receives a jolt of productive vitality that can carry it for centuries. Yuri Romanenko, on returning to Earth after what was then the longest space flight in history, said “The Cosmos is a magnet… Once you’ve been there, all you can think of is how to get back.